Control for duplicating lathe cutting toolholders



March 9, 1954 H R, BRUET 2,671,432

CONTROL FOR DUPLICATING LATHE CUTTING TOOLHOLDERS Filed Feb. 8, 1952 5 SheeiS-Sheet l HENRI Rf/vf BRI/ 737 M @w/ A TTORNEYS March 9, 1954 H, R BRUET 2,671,432

l CONTROL FOR DUPLICTING LATHE CUTTING TOCLHOLDERS Filed Feb. 8. 1952 5 Sheets-Sheet 2 B/ MVM A TTORNEYS H. R. BRUET March 9, 1954 CONTROL FOR DUPLICATING LATHE CUTTING TOOLHOLDERS Filed Feb. 8, 1952 3 Sheets-Sheet 3 INVENTOR Hmm .RENE BRUET Bf Patented Mar. 9, 1954 CONTROL FOR DUPLICATING LATHE CUTTING TOOLHOLDERS Henri Ren Bruet, Neuilly-sur-Seine, France Application February 8, 1952, Serial No. 270,665

Claims priority, application France February 8, 1951 2 Claims.

This invention relates to automatic reproducing-lathes in which the tool-holder support is controlled through hydraulic means, comprising a movable control cylinder and a fixed piston mounted therein, and a feeler in Contact with a model-piece or template, carried by the same frame as the tool-holder support. The object thereof is a feeder of a simple and advantageous construction permitting to achieve the control very accurately.

A feeder according to the invention comprises four piston valves having pistons controlled by a tumbler so that when two of said valves are open, the other two are closed, and reversely, two of the valves that are in the same position being intended to be placed on pipes respectively connecting the inletting of a feeding fluid in one of the chambers of the control cylinder of the reproducing lathe and the outletting of said fiuid into the second chamber or opposite chamber of said cylinder, While the other two valves are intended to be placed on pipes respectively connecting the inletting of the feeding fluid to the second chamber of the cylinder and the pushing back of said fluid to the rst chamber of said cylinder, the

tumbler being urged by elastic means to the position corresponding to the contact of the feeler and the tool respectively with the model-piece or template and the rough-shaped piece to be machined and being mechanically connected to the feeler, so that when the latter is in contact with the model-piece or template it may cause the tumbler to pivot against the action of said elastic means.

When the feeler comes into contact with the .Y

model-piece or template, it causes the tumbler to pivot in opposition to the action of the elastic means producing a very small backward motion of the frame carrying the feeler and the tool.

Such a very small backward motion produces a the travel of said pistons may be very short, the

sensitiveness of the feeler is very great and its motions are at once imparted to the tool so that the machined piece is quite similar to the template.

The diameter of the head of the piston of each transmitting I 2 valve will preferably be scarcely greater than that of the boring in which the body of the valve is slidable. Owing to this fact, the strength required for the opening of a valve is very small.

A particular embodiment will now be described with reference to the attached drawings by way of example which is in no way limitative, of a reproducing-device with hydraulic transmitting means and provided with a feeder according to the invention; of course, all the characteristics appearing from the description and the drawings are part of the invention.

In the drawings:

Fig. 1 is a vertical cross-section of the reproducing device.

Fig. 2 is a vertical cross-section of the feeder along II--II of Fig. 3.

Fig. 3 is a vertical cross-section perpendicular to that of Fig. 2.

Fig. 4 is a plan view thereof.

Fig. 5 is a horizontal cross-section of a detail.

Figs. 6 and 7 are diagrammatical illustrations of the operation of the present device.

The reproducing assembly shown on Fig. 1 comprises a frame I mounted to be slidable on a bed-plate 2 integral with the transverse carriage of the lathe. On the frame I, are secured, on the one hand, a tool-holder support 3 and, on the other hand, a fluid-tight reservoir 4 containing the feeding fluid which may be oil, for instance, in which is provided a pump 5 connected to a motor not shown on the drawings. The inletting pipe of the pump 5 opens in a filter 6 bathing in the feeding fiuid while the back flow pipe I is connected to a cylinder 8 secured on the frame I through a feeder referred to, in a general way, as 9; the oil is pushed back through a pipe I0. In the cylinder 8 is mounted slidable a piston II whose rod I2 is fixed at its extremity to the bedplate 2. The feeder is controlled through a feeler I3, as will be later on described and I4 is a delivery valve.

The feeder (Figs. 2 to 5) comprises a case I5 in which are provided cylindrical housings having each a wider part Ita, I6b, Ic or |611. The recesses Ita and Mib, on the one hand, and IEc and I'd, on the other hand, communicate with each other. In each of said recesses is mounted a sli-dable piston llc, Hb, I'Ic or IId, a part of which is wider, such as I8, and has a slightly greater diameter than the recess with which it cooperates so that the annular edge I9 of said recess serves as a valve-seat. The bodies of the pistons have a diameter comparatively smaller than the cylindrical recess so that between said to the back flow pipe 1 of the pump 5 and to the On the other hand, each andelivery pipe I0. nular space a and 20h is connected yto one extremity of the cylinder 8 respectively through a pipe 23 and a pipe 24.

The pistons I1 are held at one extremity by adjustable bolts 25 screwed in a tumbler 26 mounted for rotation in a case I5 about a shaft 21. Said pistons are retained against the screws 25 by springs 28 interposed between said pistons and adjustable abutments 29 screwed in a piece 30 fixed on the case I5 by means of a screw 3|. Itis apparent that when the pistons |1a and I'Id are in their open position, the pistons I'Ib and I'lc are in their closed position or reversely. The screws 25 are so adjusted that the travel of the pistons be very short, of the range of a few mms. The case I5 is closed at its extremities by lids 32 and 33 fixed by screws such as 3&2.

In a recess 35 of the casing I5 is mounted slidable a pusher-piece pressing on the tumbler 26 by means of a spring 31 fixed by an adjustable abutment 38. Said push-piece tends to retain the tumbler in the position corresponding to the open position of the pistons I'la and Hd during which the tool is in contact with the rough-shaped piece as will be explained later on.

The feeler I3 is jammed in the boring of a rod 39 fixed by a bolt El on one extremity of a lever in the shape of a fork di. The latter is pivotably mounted on a shaft [i2 in an auxiliary frame 43 xed to the cylinder 8. 'I'he other extremity of the lever lll has a pawl in contact with a teat nut d6 secured in the tumbler 26 eccentrically with respect to the shaft 21 of said tumbler. A hand control lever 4l is mounted pivotably in the frame d3 and carries a camshaped piece 48 cooperating with a pawl i9 fixed on the lever Il so that when the lever 131 pivots in the proper direction it causes the lever 4| to Y pivot also.

A feeder according to the invention operates in the following way: supposing, to begin, it s l in the position shown on the drawings, the tumbler 26 is urged by the spring 31 into the position corresponding to the open position of the pistons I'ia and IId and the other two, in their closed position. Then the oil flows into the chamber 5B of the cylinder through the pipe 1, the annular spaces 16d and 28d, the pipe 22, the annular space 2Gb and the pipe 24 while the oil held back in the opposite chamber 5I of the cylinder flows back to the reservoir l through the pipe 23, the annular spaces Ilia and 20a and the pipe I0. The frame I then changes place with respect to the bed-plate 2 until the tool and the cylinder through the pipe 1, the annular spaces E IBd, I6c and 20c, the pipe 2|, the annular spaces 20a and the pipe 23, while the chamber 50 is caused to communicate with the reservoir 4 through the pipe 24, the annular spaces 20h, Ib and IGa and the pipe I0. Thus is the tool driven away from the rough-shaped piece until the feeler leaves the template and the tumbler 26 resumes its former position under the action of the spring 31.

l The process which has just been described takes place again; the tool thus forms out of the rough-shaped piece to be machined a piece identical to the template. As the pivoting angle of the tumbler` 26- is very small, the displacement of the feeler I3 is transmitted practically at once to the tool and the piece machined by it is strictly identical to the template.

The operation of the lever B1 permits to make the lever 4l pivot in the direction corresponding to the stopping of the working tool.

It is obvious that any modification can be made in the embodiment which has beendescribed without departing from the limits of the invention.

What I claim is:

1. In a lathe duplicator mechanism including a cutting tool controlling piston and cylinder therefor, a piston control valve comprising a cylinder block having two pairs of bores provided therein, said cylinder block further having a pair of passageways each connecting a bore from each pair thereof together, said cylinder bores each having an annular recess in the wall dening said bore with the recesses of each pair of bores being in communication, means for introducing fluid under pressure to a recess of a bore of one of said pairs thereof, said cylinder block having a further pair of passageways for being connected to said cylinder on opposite sides of said piston with each passageway connected to a bore of the second pair thereof, a plurality of pistons each having a reduced portion and being slidably mounted in one of said bores, a tumbler for reciprocating said pistons and arranged for moving one piston of each of said pair of bores in one direction for closing off the recesses of said bore with the remaining pistons moving in an opposite direction for having their reduced portion providing a passageway between their respective bore recesses and said interconnecting passageways, template controlled means for moving said tumbler, resilient means tending to move said tumbler for holding the pistons of one pair of bores in their recess closing position, said cylinder block having an exhaust passageway connected to a bore of said second pair thereof, and means tending to move said pistons towards said tumbler.

2. In a lathe duplicator mechanism including a cutting tool controlling piston and cylinder therefor, a piston control valve comprising a plurality of cylinders, a plurality of pistons each slidably mounted in one of said cylinders and having a recessed medial portion, said cylinders each having an annular recess provided in the bore wall at one end portion thereof for being closed by the head of its respective piston and opened by the recessed portion of saidpiston, one of said cylinders having an inlet port for connection to a source of fluid under pressure, a second cylinder having an outlet port, said inlet cylinder having its bore recess in communication with the bore recess of a third cylinder, said outlet cylinder having its bore recess in communication with the bore recess of a fourth cylinder,l said inlet cylinder having a medial portion of its bore in communication with a medial portion of the bore of said fourth cylinder, said outlet cylinder having a medial portion of its bore in communication with a medial portion of the bore of said third cylinder, said outlet cylinder further having a port provided in a medial portion of the bore thereof for being in communication with an end portion of the bore of said controlling piston cylinder, said fourth cylinder having a port provided in a medial portion of the bore thereof for being in communication with the opposite end portion of the bore of said controlling piston cylinder, a shaft mounted laterally of said pistons, a tumbler pivotally mounted on said shaft and arranged for reciprocating said pistons with the pistons of said outlet and inlet cylinders moving together in an opposite direction to the pistons of said third and fourth cylinders, resilient means tending to hold said pistons against said tumbler, template controlled means for pivoting said tumbler and resilient means tending to hold said tumbler with the pistons of said inlet and outlet cylinder in their recess opening position.

HENRI REN BRUET.

References Cited in the le of. this patent UNITED STATES PATENTS Number Name Date 1,896,052 Ferris Jan. 31, 1933 2,464,626 Waterson Mar. 15, 1949 FOREIGN PATENTS Number Country Date 619,123 Great Britain Mar. 3, 1949 652,537 Great Britain Apr. 25, 1951 

